The present invention concerns a collector support for lead/lead oxide batteries.
In this and other types of batteries, the electrodes are made of a support which confers mechanical strength and long-term geometrical stability. The support, made of an inert mineral or organic material, is usually covered or coated with one or more conductive layers which serve to facilitate the mobilization and flow of electrons mobilized during the charging or discharging process. For this reason, these supports are sometimes called current collectors or "collector supports" which term will be used herein. To make an electrode, active material is pasted onto this collector support, the electrode being formed by this assembly.
The manufacture of lightweight collector supports made of a core of polymer coated with lead has already been suggested for the electrodes of lead/lead oxide batteries with high energy per mass. The invention is based on the observation that to obtain good performance both per mass and per volume, especially during extreme conditions of charge and discharge, it is essential to precisely define the geometrical shape of the collector supports and their dimensions. Furthermore, the cohesion of the active materials must be maintained to achieve long electrode lifetimes, especially for positive electrodes, which in particular also require close control of the collector support's geometrical configuration.
As will be explained below, taking into consideration all of these constraints is not at all easy inasmuch as some of the parameters in question are contradictory, and vary oppositely to one another, especially in a non-linear manner. According to the operating conditions encountered, the variations of one and the same parameter may occur in one direction or in the opposite direction.
After extensive tests, the Applicant has developed a collector support whose structure and constitution enable the production of highly efficient electrodes for lead/lead oxide batteries, bearing in mind the non-linear phenomena set out above and their often erratic and surprising evolution.